Of interest is commonly owned copending application Ser. No. 821,511 entitled "X-ray Apparatus" filed Jan. 15, 1992 in the name of G. Harding et al.
Such an arrangement is known from EP-OS 360 347 corresponding to U.S. Pat. No. 5,008,911 incorporated by reference herein. It can be used for luggage control in order to identify, for example, explosives or drugs. In fact it has been found that these substances show on account of their crystalline structure a spectrum produced by diffraction and having distinctly pronounced peaks, which is characteristic of these substances and can be clearly distinguished from the spectra of other substances, which are generally taken along in pieces of luggage.
In the known arrangement, in which the diaphragm arrangement has a circular opening, so that the primary beam of radiation in the examination region generates the surface of a circular cone, the second diaphragm arrangement comprises several tubes, which are arranged concentrically to each other and through which the detector arrangement comprising several annular detector elements is struck by scattered radiation. As a result, the examination region is subdivided into a number of sections (in the form of parallel disks) corresponding to the number of the detector elements; each detector element detects the scattered radiation for one of these sections.